A.1.24 The regex Directory

Henry Spencer's Regular Expression library for support of REGEXP
function.

This is the copyrighted product of Henry Spencer from the
University of Toronto. It's a fairly-well-known implementation
of the requirements of POSIX 1003.2 Section 2.8. The library is
bundled with Apache and is the default implementation for
regular-expression handling in BSD Unix. MySQL's Monty Widenius
has made minor changes in three programs (debug.c, engine.c,
regexec.c) but this is not a MySQL package. MySQL calls it only
in order to support two MySQL functions: REGEXP and RLIKE.

Some of Mr Spencer's documentation for the regex library can be
found in the README and WHATSNEW files.

One MySQL program which uses regex is
\cmd-line-utils\libedit\search.c

This program calls the 'regcomp' function, which is the entry
point in \regex\regexp.c.